Automatic fuel shut-off system



Filed July 5, 1960 INVENTOR. fir fh ur Dick/m/fz Y W4 dim %3 lia-flu W ATTORNEYS United States Patent ()flice 3,028,849 AUTQMATIC FUEL SHUT-OFF SYSTEM Arthur Biclrholtz, 4747 N. Clark St., Chicago, lll. Filed July 5, 1960, Ser. No. 40,766 1 Claim. (Cl. 123-179) This invention relates to automatic safety devices for internal combustion engines, and, more particularly is directed to improved methods and means for controlling the flow of fuel to the engine as a function of engine operating conditions.

Heretofore explosions have occurred on boats, ships and the like because of hydrocarbon fuel and hydrocarbon fuel vapor accumulation in the bilge. I have discovered that a portion of the fuel found in the bilge flows from the carburetor, particularly the float bowl. The float in the float bowl, being subjected to vibrations and motion of the body of water in which the boat is located, may stick and permit flow of fuel from the gas tank into the carburetor float bowl. The flow of fuel continues until the float is released and stops flow to the bowl. Meanwhile, the excess gasoline or other hydrocarbon fuel flows through the air vent into the bilge. The accumulation of the fuel in the bilge thus presents a fire and explosion hazard.

With my invention, I substantially eliminate the possibility of gasoline flow from the carburetor float bowl into the bilge.

It is then a feature of the present invention to provide means for preventing flow of fuel from the fuel tank to the carburetor wherein a normally closed valve is positioned in the flow line from the fuel tank to the carburetor and is operatively responsive to the engine operating conditions for opening-thereof to permit flow to the carburetor. i

It is therefore an object of the present invention to provide means for automatically controlling flow of fuel from the fuel tank to the carburetor.

It is another object of the present invention to provide valve means for controlling flow of fuel from the fuel tank to the carburetor.

It is still anotherobject of the present invention to provide automatic valve means operatively responsive to engine operating conditions for controlling flow of fuel from the fuel tank to the carburetor.

It is a further object of the present invention to pro vide means which automatically terminate flow of fuel from the fuel tank to the carburetor as a function of engine operating conditions.

It is a still further object of the present invention to provide means for terminating flow of fuel from the fuel tank to the carburetor in response to the oil pressure in an internal combustion engine whereby the engine operation will be terminated upon decrease in oil pressure.

Yet another object of the present invention is to provide a method of controlling fuel flow from the fuel tank to the carburetor as a function of engine operating conditions.

It is a still further object of the present invention to provide means for controlling flow of fuel from a fuel tank to a carburetor which are simple and compact in construction and efficient and high speed in operation.

These and other objects, features and advantages of the present invention will become more apparent upon a careful consideration of the following detailed description when considered in conjunction with the accompanying drawing, illustrating preferred embodiments of the present invention and wherein like reference numerals and characters refer to like or corresponding parts throughout the several views.

On the drawing:

The single FIGURE is a generally schematic view illustrating a preferred embodiment of the present invention for marine applications.

Briefly stated, the present invention involves positioning normally closed automatic valve means in the flow line between the fuel tank and carburetor of an internal combustion engine which is operatively responsive for opening to the operating conditions of the engine. For this purpose, a solenoid valve may be connected in the flow line and a pressure switch actuated by the oil pressure in the internal combustion engine employed to open the valve when a predetermined pressure has developed in the oil pressure lines of the engine. Thus, when the engine oil pressure reaches the level for which the pres-' sure switch is calibrated, the switch will be maintained in the closed position and thereby energize the solenoid and maintain the solenoid in the open position as long as the pressure level is maintained. When the oil pressure level drops below the operating level, from any cause whatsoever, the pressure switch will be opened thereby closing the solenoid valve and terminating the flow of fuel from the fuel tank to the carburetor. To initiate operation from the control system, the pressure switch may be connected in circuit with the vehicle starter switch, and, when the starter switch is actuated, an impulse is transmitted to the pressure switch and solenoid valve to permit a portion of fuel to flow from the fuel tank to the carburetor for replacing the fuel which flows from the float bowl through the induction conduit. This initial impulse is sufficient to permit enough fuel to flow into the engine toraise the pressure in the oil pressure line to the level suflicient to permit continuous operation of the control system.

Since the conduit leading from the fuel tank to the carburetor or fuel distributing means operates on a gravity feed basis, particularly for marine applications, the use of the solenoid valve in the conduit is facilitated. More over, the solenoid valve is cooled by the flow of fuel through the conduit, andthus temperature is maintained across the valve under tolerable limits. With my invention the possibility of human error is substantially eliminated. If, for any'reason, the engine fails to start, the fuel flow is immediately and automatically shut off, again preventing overflow and flooding of the carburetor, major causes of engine explosion.

If the internal combustion engine starts and is functioning properly, the low oil pressure switch wired in series with the solenoid valve energizes the solenoid valve and maintains the valve in open position thus permitting the required gas flow from the fuel tank to the carburetor to maintain the proper combustion mixture. The pressure switch, which may be actuated by the oil pressure in the engine, may be calibrated to open the circuit at any desired pressure level, for example, from about 7 to about 10 p.s.i. Thus if the oil pressure falls below this level, the valve in the line between the-fuel tank and the carburetor will automatically close, thereby starving the engine of its fuel supply and causing the engine to shut down.

Preferably the solenoid is spring-biased to closed position so that if an electrical failure occurs in the solenoid circuit, no current is sup-plied to the solenoid and the valve spring will automatically close the valve.

The system of this invention, generally indicated by reference numeral 10, is designed to control the supply of fuel from a fuel tank 11 to an internal combustion engine 12 which includes a carburetor 13, a starter 14 and an oil pressure gauge 15. As is conventional, the starter 14 has one terminal 17 connected to one terminal of a battery 18, for example the negative terminal, and the starter 14 has Fatented Apr. .10, 1962 a second terminal 19 connected through a relay contact 20 to the other terminal of the battery 18. A relay coil 21, controlling the contact 20, has one terminal connected to the negative terminal of battery 18 and a second terminal connected through a starter switch 22 to the positive terminal of the battery 18.

In accordance with this invention, a valve 23, controlled by a solenoid 24, is installed in a fuel line 25 between the fuel tank 11 and the carburetor 13. The solenoid 24 has one terminal 26 connected to the negative terminal of battery 18 and a second terminal 27 connected through a relay contact 28 to the positive terminal of the battery 18. A coil 29, controlling the relay contact 28, is connected in parallel with the relay coil 21. Through a suitable fitting 30, a pressure switch 31 is coupled in a pressure line 32 between the engine and the oil pressure gauge 15. The pressure switch may be connected in any portion of the pressure line, as required.

in operation, the valve 23 is closed when the solenoid 24 is deenergizcd, to prevent flow of fuel from the tank It to the carburetor 13. In this'way, spillage of fuel from the carburetor 13 will not occur even though its fiont may be stuck in a position in which the float valve is open. When the starter switch 22 is closed, the relay 21 is energized to close the contact 20 and energize the starter 14-. At the same time, the relay 29 is energized to close the contact 23, and thereby energize the solenoid 24. The valve 23 is thus opened at substantially the same time that the starter 14 is energized, to permit supply of sufiicient fuel to the carburetor 13 to permit the engine 12 to start. After the engine starts, the starter switch 22 is, of course, opened to deenergize the relays 21 and 29. However, the oil pressure of the engine has built up to close the pressure switch 31, to maintain energization of the solenoid 24, and thus maintain the valve 23 in its open position so long as the engine is running and so long as there is sufficient oil pressure. When the engine is shut off the drop in oil pressure will cause the pressure switch 31 to open to thereby deenergize the solenoid 24 to close valve 23. If the oil pressure should drop because of insufiicient oil in the engine, or due to damaged bearings, the switch 31 will open to deenergize the solenoid 24, to thus close the valve 23 and thereby cut off the supply of fuel to the engine.

The system 10 thus provides the proper supply of fuel to the engine while preventing supply of fuel thereto at times when the supply of fuel would create a fire hazard or cause damage to the engine.

It will be appreciated that not only does the automatic fuel control system of the present invention prevent carburetor over-flow and fuel syphoning because of a possi ble malfunction in the needle and seat mechanism in the float chamber of the carburetor bowl, but also eliminates possible gas leakage due to faulty gas lines between the fuel tank and carburetor, particularly where the valve means are positioned adjacent the fuel tank.

Where the apparatus of the present invention is employed in circuit with the ignition means of the vehicle, the fuel shut-off valve means will not open if for any reason the ignition wires are jumped.

It will be understood that other modifications and variations may be effected without departing from the spirit and scope of the novel concepts of the present invention.

1 claim as my invention:

In a fuel flow control system for an internal combustion engine having an electric starter and a pressurized oil system, a fuel supply, electrically operated valve means between said fuel supply and said engine, pressure switch means responsive to engine oil pressure and arranged to close when the oil pressure exceeds a certain value, a current source, relay means including a first contact arranged to be closed in response to energization thereof, relay means including a second contact arranged to be closed in response to energization thereof, a starter switch connecting both said relay means to said current source to energize both said relay means and to close both of said first and second contacts, means connecting said current source to said starter through said first contact to energize said starter upon closing of said starter switch, means connecting said current source to said electrically operated valve means through said second contact to open said valve means and to supply fuel to said engine upon closing of said starter switch, and means connecting said pressure switch means in parallel with said second contact to allow deenergization of said starter upon opening of said starter switch while maintaining energization of said valve means as long as oil pressure exceeds said certain value.

References Cited in the file of this patent UNITED STATES PATENTS 2,370,249 Korte et al Feb. 27, 1945 2,390,084 Edwards Dec. 4, 1945 2,469,942 Armstrong et al May 10, 1949 2,537,354 Korte et al Jan. 9, 1951 2,609,809 Parker Sept. 9, 1952 2,771,068 Jettinghotf Nov. 20, 1956 

